We review three well-known historical chatbots: ELIZA [1]}, PARRY [2]}, and ALICE [3]}. ELIZA was a chatbot based on a model of Rogerian psychotherapy. Figure REF  shows an example excerpt of an interaction with ELIZA originally published in 1966. ELIZA relied on very simplistic dialog management – canned phrases and simple re-write rules of the user's input with catch-all fallback responses to handle unmatched input phrases. Despite the simplicity and limitations of ELIZA, some users engaged in long conversations with ELIZA. Ultimately, ELIZA highlighted the potential power of chatbots while the limitations would indicate the need to support more flexible conversations.
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